Adding 2darrays using Intstream in Java

By Harish Gowda | | 2 minutes

In this tutorial we will learn how to add elements from two 2d arrays using Intstream in java.

In the below example we have created two 2D Arrays.

Steps:

  1. First loop through rows. We can iterate over the rows of both 2D Arrays using IntStream.range(0,num1.length).
  2. Next loop through columns. For each row we can iterate over the columns using IntStream.range(0,num1[i].length).
  3. We then add corresponding matrix since we have indexes of both 2d arrays using map() function.
  4. Once we are done iterating through arrays we convert them to 2d array and return the result.
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package examples;

import java.util.Arrays;
import java.util.stream.IntStream;

public class App {
public static void main(String[] args) {

        int[][] num1 = {
                {1,1,1},
                {1,1,1},
                {1,1,1}
        };
        int[][] num2 = {
                {2,2,2},
                {2,2,2},
                {2,2,2}
        };

        int[][] result = sum2DArrays(num1,num2);
        Arrays.stream(result)
                .map(Arrays::toString)
                .forEach(System.out::println);
    }

    public static int[][] sum2DArrays(int[][] num1,int[][] num2 ){

        return IntStream.range(0,num1.length) // Loop through row
                .mapToObj(i -> //Each row
                    IntStream.range(0,num1[i].length) // Loop through columns 
                    .map(j->num1[i][j] + num2[i][j]) // Sum the array
                    .toArray()
                ).toArray(int[][]::new); // Convert to 2D array

                /* [3, 3, 3]
                   [3, 3, 3]
                   [3, 3, 3]                   
                 */


    }
}